Bottle capping machines utilize spindles that progress through a series of motions to systematically pick up caps, corks, or other closures, and apply them to bottles. Bottle capping machines can be used to apply a variety of closures, including but not limited to screw-on, snap-on, or roll-on caps, and corks made from natural or synthetic materials. Bottles can be made from any suitable material including but not limited to glass, plastic aluminum, or the like.
The motions of the capping spindle are effected by a stationary barrel cam that defines a cam track or groove for dictating the vertical path in which the spindle will move as it revolves about the cam. For proper application of bottle closures, the barrel cam track, which dictates the vertical motion of the spindle, must be matched to the thread pitch and exterior geometry of the cap being applied. The barrel cam is designed to work with a specific thread finish (e.g., single, double, triple lead, corker, snap-on, or roll on), which limits the variety of products that may be capped on any given machine. Changing a barrel cam on a capping machine is time-consuming, often requiring a full day's down-time, and the work must be performed by skilled technicians.
Several techniques have been developed for changing the barrel cam on a bottle capping machine to accommodate different types of products. The first technique utilizes a split barrel cam that can be unbolted and replaced with another barrel cam having a different track. However, removal of the split barrel cam requires the removal of all capping spindles, a crew of skilled technicians, and considerable down-time. The second technique utilizes a separate servomotor connected to each spindle with programmable logic controls (PLC) that allow a spindle to vary its path using software. A barrel cam and cam follower are not required. However, from a controls perspective, this is a complex solution that requires maintenance skills beyond those of the typical bottling industry staff. It is also a relatively costly solution.
A third technique utilizes a barrel cam with dual tracks and two unique spindle assemblies for use with each track. To adjust the barrel cam track, one of the spindle assemblies is removed from the machine and the other spindle assembly is installed. With this technique, a change-over can be accomplished more quickly, however, the technique requires significantly more money in start-up and operation and maintenance costs since two sets of spindle assemblies (and possibly headsets) are involved.
A fourth technique utilizes an independent headset drive (IHD) arrangement that allows the spindle revolutions to be decoupled from the capping turret revolutions using a servomotor and idler gears. Compared to standard capping techniques, the fourth technique requires drivetrain and controls that are costly and complicated. To avoid damaging the cap during application, control can be maintained by adjusting the rpm to a much higher or lower value than is normally possible. However, the fourth technique tends to address symptoms of the problem rather than providing a true solution because the rotational speed of the spindle is used to compensate for a compromised cam profile.
Thus, there exists a need for a barrel cam and spindle assembly that can accommodate multiple products without requiring significant cost down-time technical expertise, and maintenance. The assembly should allow the spindle to be operated by a selected one of multiple tracks on a barrel cam with relatively little effort. Ideally the assembly would mitigate the need to change the barrel cam and spindle, and would not require the use of any parts other than those already contained on the spindle.